Reversing-gear mechanism



Nov. 4, 1930. F. N. BAR D REVERSING GEAR MECHANISM 2 Sheets-Sheet 1Filed Nov. 28, 1921 jzverzr'.

Nov. 4, 1930. F BARD 1,780,329

REVERSING GEAR MECHANISM Filed No r. 2 1921 2 Sheets-Sheet 2 PatentedNov. 4, 1930 PATENT OFFICE FRANCIS N. BARD, 01" HIGHLAND PARK, ILLINOISREVERSING-GEAR MECHANISM Original application filed July 31, 1920,Serial No. 400,478. Divided and this application filed November Thepresent invention relates in general to reversing gear mechanism andmore particularly to mechanism of the character referred to operable bymechanical power, and

5 has special reference to the provision of an improved form of fluidpressure driven reversing gear mechanism.

The principal objects of the, present invention are the provision of animproved .10 form of fluid-operated reversing gear mechanism; theprovision of an improved gearing, and more particularly, irreversiblegearing, for establishing a driving connection between a suitably drivenelement and the mechanism to be moved thereby; the provision of animproved valve mechanism for controlling the flow of fluid to the partsto be actuated; the provision in general of an improved arrange ment ofmotion transmitting elements, and more especially one adapted foroperating a controlling valve; the provision of a power driven reversinggear mechanism of means whereby the mechanism may be actuated manuallyfrom an external point in the defeet of power actuation; the provisionof .means for providing an auxiliary or supplemental source of power foractuating the reversing gear mechanism, in certain contingencies, and ofautomatically acting controlling mechanism therefor; together with suchfurther and additional objects as may be below set forth. 7

Mechanisms of the character referred to have a general field ofusefulness, and are of particular utility in the operation of the valvemechanism of large steam engines.

This application is a division of my application, Serial No. 400,47 8.

For purposes of illustration, therefore, the inventions have been shownstructurally embodied in form adapted for employement as gearing foropening and closing, and for reversing, the valve mechanism of railwaylocomotive engines.

In the accompanying drawings, therefore- Figures 1 and 2 arerespectively a longitudinal elevational view, and a top plan view, ofthe casings of the improved mechanisms, together with the associatedelements extend- Serial No. 518,426.

ing respectively to the engineers cab and to the tumbling shaft of thelocomotive;

Figure 3 is a longitudinal sectional view, taken substantially centrallyof the device of Figure 2, on the line 3-3 thereof;

Figure 4 is a plan view, partly in section, illustrative of certainelements indicated in side elevation in Figure 3 taken on line ll ofFigure 3;

Figure 5 is an enlarged fragmentary elevational view,'partly in section,of certain details of the construction of Figure l, illustrative ofother relations assumed bycertain of the parts; and

Figures 6, 7 and 8 are fragmentary sectional views illustrative ofdetails of construction and arrangements of ports and passages, suchviews being taken on lines 6-6, 7-7, and 88 of Figure 5.

Referring first to Figures 1 to 3 of the drawings, it will be observedthat in the present invention there is provided a casing structure, 10,having cylinder portions 11,12,within which is mounted a pistonstructure including heads 18, 14, connected by a rod 15. The casing, 10,is preferably made integral with the cylinder portions in alignment andis provided with an integral lateral extension to form a housing, 19,for certain gearing elements hereinafter to be described.

The rod, 15,is non-circular and is supported in the casing, 10, by meansof a step-bearing, 16, which also serves as a bearing for the reducedshaft, 17, of the spiral worm, 18, mounted in said housing, 19.

The worm is held in position in the housing, 19, and againstlongitudinal movement by means of bushing, 20, and is in mesh with asegmental rack, 21, carried on a shaft, 22, in a housing, 23.

Reverting to the shaft, 17 and the rod, 15,.

these two elements have a rack-and-pinion engagement, (see Figure 4) andclearly the length of the rack on the rod, 15, and the re 'lationship ofthe number of teeth on the rack to those on the pinion is such that thefull throw of the rack-rod, 15, will cause a number of revolutions ofthe spiral gear, 18.

As a result of this plural rotation of the spiralgear, the turns of theworm, 18. can

be quite closely approximated, thus producing a more eflicient lockingeifect against reversing by the segment, 21, without increasing theangular throw of the segment.

As means for the operation of the piston structure, there are formedwithin the casing the passages 31 and 32 for the purpose of admittingand exhausting fluid under pressure to and from the opposite ends of thecasing structure. This admission and exhaustion of fluid is controlledby a valve mechanism shown generally at 33 in Figures 5 and 8.

The said controlling valve structure comprises a valve chamber, 34, withwhich the passages 31 and 32 communicate. This valve chamber is formedby securing a cup-shaped block, 30, to the casing 10, by means ofscrews, 29, (see Figure 7).

Fluid under pressure is introduced into the chamber 34 by means of apipe, 35, connected to a suitable source of supply (not shown) andcontrolled by a cab-valve under the hand of the engineer. From thechamber, 34, exhausted fluid is vented to the atmosphere at the pointindicated at 36 (Figure 7).

For establishing the desired communications between the various passagesand ports, there is employed a suitable valve disposed in the chamber34. This valve is conveniently one of the rotating segmental disc type,37, provided with a segmental groove, 38.

It will be apparent from viewing Figure 5 of the drawing that thecontour of the disc, 37 is such that the orifices of both of thepassages 31 and 32 are covered in one position of the disc, 37,hereinafter referred to as lap .position and whenever the disc, 37, ismoved in either direction from such lap position, the groove, 38, willbring one of the passages 31, 32 into register with the passage leadingto the exhaust port, 36, (see Figure 7), and at the same time uncoverthe orifice of the other of such passages and permit the influx of fluidunder pressure, thus insuring at all times an equilibrium of pressureagainst the several piston heads and permitting the valve gear to be setat any desired cut-ofl and held against creeping. It will be readilyseen that all of the desired functions of the controlling valvemechanism are accomplished by the use of but a single moving valvemember.

As means for operating the valve mechanism, that is, for turning thedisc, 37, to any desired extent, there is employed a link, 39, fixed onthe stem, 40, of the valve 37. Such link is pivotally connected by arod, 41, to one arm, 42, of a bell-crank lever, 43, in turn pivoted toan annulus, 44, surrounding the shaft, 22. The so-called short reach rod47 is pivotally connected as indicated at 45 to the arm, 46, extendingfrom the annulus, 44.

From the foregoing description, it will be understood that bymanipulation of this lever and thereby movement of the short reach rod47, the engineer can move the disc, 37,

into any desired position, and thereby not only impart such forward orreverse movement to the locomotive as may be desired, but also set andhold the valve gear at any desired cut-ofi'..

For the purpose ofvrestoring the valve, 37, from any off-lap position tolap position, after imparting the necessary movement to the piston rod,15, and associated parts and thereby holding the valve gear at thedesired cut-ofl, the arm, 48, of the bell-crank lever, 43, has a lostmotion connection by the pin and slot arrangement, 50, with the lug, 52,projecting from the annular portion, 54, of the lever, 49, pivotallyconnected at its lower end to the so-called long reach rod 51, as isclearly to be seen on inspection of Figure 5.

As is obvious on viewing Figures 3 and 5 when the valve, 37, is moved toan off-lap position, as for example as shown in Figure 5 where theleft-hand end of the groove, 38, is in communication with the passage,31, and the right-hand end of such groove terminates at the pointindicated at 38*, the shaft will be oscillated as hereinbefore clearlyset forth and will in turn actuate the long reach rod 51 through thelever, 49.

This movement of the lever, 49, will in turn actuate the bell-cranklever, 43, through the pin and slot connection, 50, and move said lever,43, to the position indicated in dotted lines in Figure 5, thusrestoring the valve, 37, to lap position.

Inasmuch as at times'circumstances may arise, owing to breakage orstoppage of one of the fluid conducting lines or passages or failure offluid supply, or the piston structure may for other reasons becomeinoperable by fluid pressure, which may render it desirable to operatethe piston structure manually in order to set the valve gear in apredetermined position, I extend the shaft, 17, through and beyond thecasing, 10, and provide it with a squared terminal, 55, adapted for theapplication of any suitable means, such as a wrench, whereby it may bemanually rotated or by any available mechanism.

Having thus described my ,invention and illustrated its use, what Iclaim as new and desire to secure by Letters Patent is- .1. In a reversegear operating mechanism, a fluid operated motor including a cylinder, apiston operating in said cylinder, a rack bar connected to said pistonand extending without the cylinder, a worm arranged with its axistransversely of said rack bar and operated thereby, means connected tothe reverse gear for receiving motion from said worm, a casing for saidworm, said means and said rack bar and forming a substantially commonbearing for the rack bar, and worm, and an extension from said wormthrough said casing whereby the mechanism may be manually operated.

2. In a reversing gear mechanism in com- 1,7so,see

bination, a fluid pressure reciprocating power operated mechanism foroperating the reverse gear connecting member comprising a rack bar, apiston for actuating said rack bar,

a, segment connected to said connecting memher, a worm for moving saidsegment disposed in a lane angularly related to said rack bar in aaterally extending casing portion, said worm having an extensionconnecting same to said rack bar, a common removable bearing for saidrack bar and extension, said bearing being retained in position by therelative position of said rack bar and extension.

In testimony whereof I have hereunto signed my name.

' FRANCIS BARD.

